1. Field of the Invention
The present invention relates to a chemically activated shaped carbon, a process for producing the activated carbon and use thereof.
2. Description of the Prior Art
It has been conventional practice to recover organic solvents from gases containing the organic solvent as vaporized, by passing the gas through a layer of shaped activated carbon to cause the carbon to adsorb the organic solvent, and thereafter heating the active carbon layer to desorb the adsorbed solvent.
When gasoline engines for motor vehicles are stopped during driving, the heat of the engine operating at a high temperature is released to the environment to bring about a so-called hot-soaked state, permitting evaporation of gasoline. An active carbon layer is used for adsorbing the gasoline vapor and releasing the adsorbed gasoline for reuse for the operation of the engine.
It is desired that the activated carbon for use in these activated carbon layers be shaped carbon having high working capacity (the amount of effective adsorption) and high durability.
However, the conventional activated carbon for such uses is still unsatisfactory in the amount of effective adsorption, physical strength, etc.
Examined Japanese Patent Publication SHO 50-39635 discloses shaped activated carbon for adsorbing heavy metal ions, such as chromium ion, contained in waste liquids. The disclosed carbon is one obtained by chemically activating an organic material such as lauan flour with phosphric acid. U.S. Pat. No. 2,508,474 discloses chemically activated granular carbon, which is suitable for use as gas mask adsorbent. However, both references do not disclose specifically the physical properties of the product obtained. Further, both references do not disclose that the activated carbon obtained can be used for the adsorption and desorption cycle of gases.